This invention relates to a new method and apparatus for retrieving lobsters and similar objects from the bottom or floor of a lobster pound or other shallow water body. The invention provides for lifting the objects to the surface in a flow of water, and for handling the objects above the surface to place them on a deck or support platform floating above the water surface. This is accomplished with minimum impact, disruption, or injury to the lobsters or other objects.
Lobster pounds were first developed in Maine and adjacent states and provinces at the end of the 1800's for live storing the excess lobster catch of the summer and fall for later sale in the winter. The use of such lobster pounds more evenly distributes the supply of lobster over the year and affords speculative benefit to the pound owner who may hold the lobsters until the market is more favorable. A lobster pound is a portion at the head of a cove or harbor sometimes several acres in extent. The pound portion is diked off by a half tide impoundment or dam which holds back a portion of each outgoing tide for the sustenance of the lobsters held in the pound. When the high tide returns the water overtops the impoundment refilling, circulating, and aerating the water. Escape by lobsters, dwelling on the floor or bottom of the pound, is prevented by the dike or impoundment.
Lobsters from the summer and fall catch are deposited in the lobster pounds and as many as 100,000 lobsters may be live stored in this manner for many months in a single pound. The lobsters are fed until they become more or less dormant in the cold weather. Then, during the late winter months when the market is deemed favorable, the pound owner begins retrieving the lobsters for sale and shipment. The traditional method for retrieving the lobsters, and the only method for well over 50 years until the advent of the present invention, has been to drag for the lobsters, pulling a weighted drag, for example of chain links, over the bottom. Depending upon the bottom conditions, as many as 10% of the lobsters may be mutilated or suffer other damage during this recovery by conventional methods.
When the lobsters in the pound have been substantially depleted near the end of winter, dragging for the remaining lobsters sparsely distributed over the bottom becomes unfeasible. Therefore the pound must be drained and the remainder retrieved by hand according to the conventional methods. Such draining furthermore subjects the lobster to high risk due to cold weather etc.
Furthermore, a recent innovation in lobster pounds, is the installation of aeration systems on the bottom of the pound, to aerate and oxygenate the impounded waters during low tide. Such aeration increases the lobster holding capacity of the pound, otherwise limited by the anoxic stress suffered by the lobsters during the stagnation of low tide. The conventional methods of lobster retrieval by dragging are incompatible with such bottom aeration systems and may cause damage as the weighted drag passes over the bottom. In addition many types of bottom terrain and obstructions are incompatible with dragging, and dragging can not be used.